Apparatus for rotary drilling of wells using casing as the drill pipe

ABSTRACT

A drilling system employing casing as drill pipe and a bit section which is bodily insertable and removable through the casing and releasably attachable thereto for rotation with the casing.

United States Patent Cicero C. Brown c/o Brown Oil Tools, Inc. P.O. Box 19236, Houston, Tex. 77024 Appl. No. 803,911

Filed Mar. 3, 1969 Patented Jan. 5, 1971 Inventor APPARATUS FOR ROTARY DRILLING OF WELLS USING CASING AS THE DRILL PIPE 7 Claims, 4 Drawing Figs.

US. Cl. 175/258, 175/261 Int. Cl E21b 9/26 Field olSearch 175/257, 258, 259, 263, 267, 27]

[56] References Cited UNITED STATES PATENTS 2,330,083 9/1943 Sewell 175/258 2,890,022 6/1959 Brown 175/258 2,997,] 19 8/1961 Goodwin 175/267X 3,097,707 7/1963 Kammerer 175/258 Primary Examiner-David H. Brown Attorney-R. Werlin ABSTRACT: A drilling system employing casing as drill pipe and a bit section which is bodily insertable and removable through the casing and releasably attachable thereto for rotation with the casing.

PATENTEU M 5m SHEU 1 OF 4 A TTO/PNE) PATENTED JAN 5197 SHEETZ or 4 VPATENTED JAN 519m iev -N iw I IW AI zk fl vd ww-fs SHEET '3 BF 4 ATTORNEY APPARATUS plbyment of relatively small diameter string ofdrill'pipe to which a bit is secured, the entire string being rotatedto drill the bore hole. After a suitableintervalhasbeen drilled, sometimes only a short distance but-at othertimes for thefulldepth of the well, casing larger in diameter than the drill pipe will be run into the bore hole and subsequently cemented to seal'off the formations through which. the bore hole extendsi 'lhis necessarily involves the series of operations in which the string must be extended asIthe hole deepens, as by the addition of sections to the drillpipe, and also the entire drill stringmust be withdrawn wherever it becomes necessary to replace the bit and then reinsert it to'resui'nedrilling. Thus makingof-such 1 'so-called round trips are not only time consuming but'also create hazards of blowouts and otherundesirableconditions .in the well. After the appropriate drilling of thehole has'been i Heretofore numerous efforts have been made to. provide va system employing the casing itself as the drill pipe in order to 2 'In the'drawings: i i 'v FIG; 1 isa longitudinal, p rtlysectional viewshowing the bit sectioninserted into the casing shoe preparatory to anchoring the bit section to the casingshpq' f 2 is a view simila'r to HO. 1 showing the bit section anchored to the casihg shde and w'th-the\fnderreaniers in theirextended'position; if :1 FIG; 3 isa'viewsimilar to FIG. l'showingafishin'g tool engaged with the bit section, the parts being' s'htiwn 'afterrelease ofthe bit'section and with the underreamers n' theirretracted positiomand 1 11: FIG: 4 is'a longitudinal view of'the drilling'syste'm in aigwell bore showing-'the casing string with the bit section inplaceand thedrive connectionsat the surface; I i 1 i Referring to the drawing and considering first'FlG. 4, there is shown "a string 1 of easing C icarrying .the bitsection, designated generallyby the letter B,'-'s 'howing the bit section in place in alandingshoe l0connected to the lower end ofcas- .ing C; Atits upper-end casing' C is connected to apowerst which'functions' to rotate the. casing string during drilling.

' will ibe described. Powensub P is of thegeneral form and'conovercome some of theha'zards enumerated, as well as time loss. However,these prior efforts have notproven satisfactory for various reasons well known to those skilled inthe art;-

' l The present invention, therefore, is directed toa'n improved arrangement by which the casing may ,be employed as the drilling string and when used in combination witharet'ractable or removable bit section will perform all of the functions of drilling and easing of awell in a sequence or series of operations'which thereby greatly facilitates drilling operations? In accordance with the presentinvention .a bit'section is provided whichincludes both therprimary bit and aplurality of radially extendible and retractable iinderreamerspthe ent'ire bit section being arranged and constructed to be insertable bodily through the bore of the casing and moved to the lower end ofthe casing either on a wire line orbysimplytdropping it 3 into the casing, where, either by gravity alone :or' s'upple- 'mented by pumped fluid pressure, the bit section will be forced to the bottom of the lower end of thecasing string, {which is provided with aflanding shoe to receiveithe bit section. The bitsection is provided withilatchmeansengageable with appropriate grooves or otherlatch-receiving structtireuin" the landing shoe. The latter includes a number of keys or splines which are adapted to engage appropriatesplineslots'or grooves in the bit section'to lockithebit sectionto the casing against relative rotation whereby rotation ofthecasing'string will be effective to rotate the bit for purposes ofdrilling the well. The bit section also includes piston means connected by crank means to the underreamers which will be .actuatable from the upper end of the casing string by drillingfluid circulating through the system for purposes of extendingoractuatirigthe underreamers so as to enlarge the boreihole=drilled by the pilot bit sufficiently to allowfree downwardrmov'ement'of the'casingbehind the bit as'the hole is being drilled;

,To withdrawth'e bit section a conventional fishing toolor spear is run into thecasing-on a wire line aiid connected to the bitsection, whereby an upward pull appliedto the=fishing tool will be effective to retract the underreamers andzrelease the bit section from the'landing shoe .to which it has "been anchored. The spacing arrangement, between the under-; reamers and latching dogs is so designed as toassurethat-the "underreamers are fully retracted before-the bit section is released;therebyavoidingdamageito the underreamers which might otherwise occur if .they 'were not 'completelyretracte when they pass the lower end of the landing shoe. Other and more specific objects and advantagesofthisin- 'v'ention will become more readily apparentjfromthefollowing detailed descriptionwhen-readin conjunction with-the accompanying-drawing which illustiat'es auseful-embodirnentzin' ac- -eordance withthe present-invention.

structiori' disclosed inimy copending application, Ser. No. 736,179, filedIJun. 'll,'l968.'.A"suitable drive connection betweenthe power sub and; the easing is disclosed in my copending application, Seri No. 778,509, filed Nov. 25, "l 968 secured to the casing. Shoe-l0 is provided with an ir'tternall-y threaded socket :12 by which it is threadedly secured to the lower end of casing-C. Adjacent its lower end shoe 10 is pro- :videdwithtwo or moreangularly spacedpins "l4-w hichproject ia' shortdista'nce inwardly of the -b0t'6110f theshoe and form splines forpurposes which 'will'b'e explained shortly.

Bit-section Bcompr'isesabody 16 having a bore -.l7,-and is dimensioned tobe,insertable throughthe boreofcasing C and into the' bore'of shoe'l l0. Body 16 is provided about an intermediate portion -'-thereof with a plurality of "longitudinal keyways or'sp'line grooves 18 adaptedito receive the project'- ing'endsof the pins l4,-wl1ereby body 16 will be locked-to -shoe' 110 against relative rotation so that rotation-3 0i casing C will' function to rotate body 16 and itsappurtenances. Spline grooves l8-iterminate inupper end walls 19 which formstops for engagement with pins 14 to limitdownward .movernento'f thewbit body through shoe 51 0. An annular seal ring 20 5s disposedabout th'e exterior ofbodiy 16 above end-wall 19 Flo seal with the bore walliof-shoe i0; Ataypoint above seal '20, body 16 is provided 'with a plurality of radial windows or openings 22 in which .are mounted "latch do'gsf24 which are .-adapted-zto" threadedly receive a collar .30 havlingga d'ownwardly ffa cing internal shoulder 32 spaced ia'jshorlt distance belowrits upperaend. IlThelower end ofzbody' lfi-carrijes' adownwardly facinginternally threaded'socket 34 adaptedto receive the leXtemally Lthreaded. shank" 3.6 @of :a bit Ziavh'ich constitutes the pilot-bitfand-maylbeof anyconventional'design for drilling a bore 'hole to:anyvdesired nominal diametertitletfermined by thedimensions of'thepilotbit. At. a}point between 1H6 ;lower ends-of'splines '18 and socket body 12,6 is proivided with :a v.plurality of longitudinally eittending radially openingks'lots 401m which are mounted underrehmei's 212 .any suitableand knowndesign. These are pivotally-flrnounted -.on'pi-vot pins- 4j tiw'hich extendtransversely of-th'e tif- : spectii e slots for enabling the underreamers to be angularly moved so as to be radially projected and ifetracted with respect to the slots 40. The portion of bore 17 f the body which extends between windows 22 and the upper ends of slots 40, defines a cylinder 21 in which is slidably positioned an annular piston 46 having a seal ring 48 mounted in its outer periphery for slidable sealing engagement with the wall of the cylinder. Piston 46 is secured to the upper end of a square piston rod 50 having an axial bore 51 which extends downwardly between the several underreamers and projects through an axial opening 52 in the upper end of socket 34 and is slidable therein in response to the axial movements of piston 46. An annular seal ring 54 is disposed in the wall of opening 52 in sealing engagement about the lower end of piston 50. Each of the underreamers 42 is fixedly connected to an angularly extending crank arm 56 having its free end secured to a crosshead pin 58 mounted in a crosshead slot 59 fonned in the related side of exterior of piston rod 50. With this arrangement it will be seen that the movement of piston 46 downwardly will act through crank arms 56 to rotate the underreamers outwardly and upwardly while reverse movement of the piston will act to retract the underreamers.

The upper end of piston 46 is secured to a setting sleeve 60 which is inserted through collar 30 and is secured to the upper end of piston 46 about its periphery by a threaded connection 62. The upper portion of sleeve 60 is reduced in diameter externally to provide the upwardly facing shoulder 64 adapted to abut shoulder 32 on collar 30. Setting sleeve 60 is initially retained in its uppermost position at which shoulder 64 abuts shoulder 32 by means of shear pins 66 which connect collar 30 to setting sleeve 60. Just above connection 62 setting sleeve 60 is provided with an external annular relief groove 68 which is adapted to receive dogs 24 whenfthey are retracted from latching groove 26. Relief groove 68 will be disposed in registration with windows 22 and dogs 24 when the setting sleeve is in its uppermost position, as. shown in H6. 1, so that the dogs are free to move inwardly of body 16 out of grooves 26. In this position it will be also noted that piston 46 is positioned in its uppermost position at which underreamers 42 are fully retracted, also as shown in FIG. 1. The bore wall of setting sleeve 60 is provided with the annular groove 70 for engagement by a fishing tool, as will be described subsequently.

In operation, the bit section will be inserted into the upper end of casing C and will be allowed to fall by gravity through the bore of the casing until the bit is brought to a stop by the engagement of pins 14 with end walls 19 of spline grooves 18. The lower ends of spline grooves 18 ordinarily will be flared or widened circumferentially in the well known manner to guide the spline grooves 18 over pins 14 as the bit section seats in shoe 10. The parts of the bit section will be positioned as illustrated in FIG. 1 in which the setting sleeve is held in its retracted position by shear pins 66. Latching dogs 24 will thus be free to retract and are effectively retracted into relief groove 68, whereby to allow the free movement of the bit section through the casing and into landing shoe 10.

It will be understood, of course, that instead of simply dropping the bit head into the casing and allowing it to fall by gravity to the bottom, it may be lowered on a wire line or other tool string which will be releasably secured to setting sleeve 60 in a manner and by means well understood by those skilled in the art. If the force of gravity is not suflicient to cause the bit section to fall freely into the landing shoe, it will be understood that by pumping fluid, such as water or drilling mud, into the casing this will act against the restriction formed by the bore of piston rod 50 to provide hydraulic pressure sufficient to drive the bit section downwardly through the casing through any obstructing mud or the like, until it is effectively seated in shoe 10.

When the bit section is in place, pumping of fluid such asv drilling mud into the casing may be begun, or continued if 66, whereupon setting sleeve 60, piston 46, and piston rod 50 will be forced downwardly by the fluid pressure. The downward movement, acting through crosshead pins 58 and crank arms 56 will rotate underreamers 42 outwardly to the positions shown in FIG. 2. As the underreamers move outwardly and setting sleeve 60 moves downwardly the exterior portion of the setting sleeve above relief groove- 68 will pass behind dogs 24, and by reason of the enlarged diameter of the sleeve, will force the dogs outwardly into latching groove 26, thereby effectively anchoring the bit section to the landing shoe. The positions of the parts with the reamers extended and the bit section latched to the landing shoe is shown in FIG. 2.

It will be understood, of course, that the casing string will be rotated initially to cause pilot bit 38 to initiate drilling of the bore hole and as drilling proceeds, fluid pressure will be exerted against piston 46 to extend the underreamers which will radially enlarge the bore hole cut by the pilot bit to a'diameter which will allow free passage of easing string C so that it will follow directly behind the pilot bit and will continuously line the bore hole as drilling proceeds.

The drilling fluid circulation will be through hose connection H, swivel S and through a conduit in power sub P into the bore of casing C. Thence, through the bit section, the fluid flowing through the bore of piston 46 and piston rod 50 to the discharge passages in the pilot bit and the underreamers. The mud flush will return to the surface through the annulus between well bore W and easing C. The flow restrictions provided by the bore of the piston rod and the bit passages will assure the maintenance of sufficient hydraulic pressure against the piston to keep the underreamers extended as long as pump pressure is being applied.

When necessary to withdraw the bit section from the casing in order to replace or repair the pilot bit, underreamers or any other part of the bit section, a fishing tool, designated generally by the letter T, of any generally conventional form, the details of which do not form a part of this invention, will be run into the casing bore on a wire line, or tubing string if desired, and will be latched into groove 70 of the setting sleeve. On application of upward pull to the fishing string, the setting sleeve will be drawn upwardly pulling piston 46 and piston rod 50 upwardly, thereby causing underreamers 42 to be swung inwardly of slots 40. The spacing provided between relief groove 68 and shoulder 64 is selected so that underreamers 42 will swing inwardly and to the fully retracted position in slots 40 before relief groove 68 moves opposite dogs 24 and shoulders 32 and 64 are engaged. Stated otherwise, the distance through which setting sleeve 60 is moved upwardly in order to allow retraction of dogs 24 will be greater than the length of upward movement of piston rod 50 which will be required to cause the underreamers 42 to be fully retracted. In this way, the underreamers will be fully retracted and will not strike the lower end of the landing shoe before the bit head is released by retraction of dogs 24 and thereby damage to the underreamers will be avoided.

With the underreamers in their fully retracted position, as shown in FIG. 3, and dogs 24 also released for retraction into relief groove 68, the entire bit section can then be pulled out of the casing for repair, replacement or for whatever purpose may be required. If drilling for a desired interval has been completed, withdrawal of the bit section will place the casing in condition for cementing. The landing shoe may be employed to receive the usual cementing valve, if desired.

When drilling is to be resumed, the bit section, with the parts in the original retracted positions, will be returned through the bore of the casing to its lodgment in shoe 10, fluid pressure reapplied to anchor the bit section and extend the underreamers, and drilling will be resumed as previously described.

From the foregoing it will be evident that a drilling system is provided in which the casing itself which is ordinarily required tionally required in rotary drilling and for casing the well. The hazards accompanying the conventional drilling and easing operations, including those arising from round trips of the drill string, will be obviated, drilling operations greatly facilitated, and time of operation substantially reduced.

It will be understood that various changes and modifications may be made in the details of the illustrative embodiment within the scope of the appended claims but without departing from the spirit of this invention.

I claim:

1. Apparatus for rotary drilling of wells using casing as the drill pipe, comprising in combination with a string of casing and means for rotating the same:

a. a bit section bodily insertable and removable through the bore of the casing;

b. cooperating means on the bit section and the lower end portion of the casing for landing the bit section in said lower end portion in nonrotative relation to the casing;

c. said bit section comprising:

l. a generally tubular body;

ll. radially movable anchor means mounted on the body for releasably anchoring the body to the casing;

Ill. a pilot bit carried by the lower end of the body;

IV, a plurality of angularly spaced underreamers mounted on the body for radial movement between extended positions for enlarging the diameter. of the bore hole made by the pilot bit and positions fully within the perimeter of said body;

v. piston means operably connected to said underreamers and reciprocable in the bore of the body between upper and lower positions respectively retracting and extending said underreamers;

Vl. sleeve means in said body reciprocable with said piston means between upper and lower positions respectively releasing and actuating said anchor means; and

Vll. means initially securing said sleeve means and said piston means to said body in said upper positions and releasable for movement to said lower position in response to fluid pressure applied to the piston means through the casing string whereby to actuate said anchor means and to extend said underreamers. 2. The apparatus according to claim 1 wherein said initial securing means comprise shear pins.

3. The apparatus according to claim 1 wherein said sleeve means includes means adapted for engagement by a fishing tool to apply upward pull to the sleeve means.

4. The apparatus according to claim I including means operably connecting the piston means to each of the underreamers comprising:

a. a crank arm angularly secured to the underreamer; and b. crosshead pin-and-slot connections between the free end of the crank arm and the piston means. 5. The apparatus according to claim I wherein said cooperating means includes:

a. a tubular landing shoe secured to the lower end of the .casing string; b. inwardly projecting splines in the bore of the shoe; and c. spline grooves in the bit body open at their lower ends for receiving the splines in response to relative downward movement of the bit body. 6. The apparatus according to claim 5 wherein said anchor means includes:

a. a plurality of angularly spaced latching dogs disposed in openings in the wall of said body; and b. an annular latching groove in the wall of said landing shoe arranged for latching engagement with said dogs. 7. The apparatus according to claim 5 wherein said sleeve means includes an annular relief groove about its exterior which is registrable with said latching dogs when said sleeve means is in said upper position to permit retraction of said latching dogs from said latching groove. 

1. Apparatus for rotary drilling of wells using casing as the drill pipe, comprising in combination with a string of casing and means for rotating the same: a. a bit section bodily insertable and removable through the bore of the casing; b. cooperating means on the bit section and the lower end portion of the casing for landing the bit section in said lower end portion in nonrotative relation to the casing; c. said bit section comprising: I. a generally tubular body; II. radially movable anchor means mounted on the body for releasably anchoring the body to the casing; III. a pilot bit carried by the lower end of the body; IV, a plurality of angularly spaced underreamers mounted on the body for radial movement between extended positions for enlarging the diameter of the bore hole made by the pilot bit and positions fully within the perimeter of said body; v. piston means operably connected to said underreamers and reciprocable in the bore of the body between upper and lower positions respectively retracting and extending said underreamers; VI. sleeve means in said body reciprocable with said piston means between upper and lower positions respectively releasing and actuating said anchor means; and VII. means initially securing said sleeve means and said piston means to said body in said upper positions and releasable for movement to said lower position in response to fluid pressure applied to the piston means through the casing string whereby to actuate said anchor means and to extend said underreamers.
 2. The apparatus according to claim 1 wherein said initial securing means comprise shear pins.
 3. The apparatus according to claim 1 wherein said sleeve means includes means adapted for engagement by a fishing tool to apply upward pull to the sleeve means.
 4. The apparatus according to claim 1 including means operably connecting the piston means to each of the underreamers comprising: a. a crank arm angularly secured to the underreamer; and b. crosshead pin-and-slot connections between the free end of the crank arm and the piston means.
 5. The apparatus according to claim 1 wherein said cooperating means includes: a. a tubular landing shoe secured to the lower end of the casing string; b. inwardly projecting splines in the bore of the shoe; and c. spline grooves in the bit body open at their lower ends for receiving the splines in response to relative downward movement of the bit body.
 6. The apparatus according to claim 5 wherein said anchor means includes: a. a plurality of angularly spaced latching dogs disposed in openings in the wall of said body; and b. an annular latching groove in the wall of said landing shoe arranged for latching engagement with said dogs.
 7. The apparatus according to claim 5 wherein said sleeve means includes an annular relief groove about its exterior which is registrable with said latching dogs when said sleeve means is in said upper position to permit retraction of said latching dogs from said latching groove. 